1. Field of the Invention
Finishing machines or apparatus, semiautomatic or batch-type, centrifugal finishing apparatus which is self-separating and which embodies an automatic media return.
2. Prior Art
Numerous self-separating finishing devices of the automatic, semiautomatic, and batch-type have previously been proposed. These have mainly been of the vibratory type, and have been satisfactory to the extent permitted by the permissible magnitude of the vibratory action which can be applied without damage to parts or workpieces being finished. Since vibratory apparatus of this type which has been previously available has not been able to produce high amplitudes of vibration, and especially since such high amplitudes of vibration are detrimental to finished parts during the process of separation from finishing media employed in the finishing process, serious restrictions upon the employment of such devices have been encountered. This has led to the necessity of lengthy period of vibration or gyration to complete the finishing process, with concurrent lack of economy. For such type of apparatus which was rotatable about an axis for separation employing a foraminous member or the like, the vibratory motor employed for the finishing was primarily located for effecting the finishing process and not for the separation step, so that the separation was grossly inefficient even when the vibratory means was actuated or continued in operation during the separation step. On the other hand, vertical centrifugal finishing devices have become increasingly popular during recent years because of their rapid finishing action, but efficient separation means or procedure has not previously been available for employment in or together with such centrifugal finishing devices. Accordingly, although finishing with such centrifugal finishing apparatus has to date been rapid, efficient, and economical, such advantages have been lost due to the inability to provide or even conceive a suitable and satisfactorily economical separation procedure and apparatus therefor, especially one which does not involve manual labor. Thus, at the present time the production of rotatable, vibratory finishing apparatus has essentially come to a standstill, whereas centrifugal finishing apparatus has not reached its full potential due to short-comings in separation procedure and apparatus for use in combination therewith. Although these aforesaid concepts of rotatable vibratory finishing machines and of centrifugal finishing apparatus have both been available in the art for some time, since the middle 1960's or earlier, no satisfactory solution to the aforementioned shortcomings of each has been forthcoming. It is apparent that an improved finishing apparatus and procedure, which is not characterized by the inherent shortcomings, deficiencies, and inabilities of these two separate available prior art systems, would be highly desirable and would fulfill a long-felt need in the art. Such apparatus is provided by the present invention, which eliminates the inherent shortcomings and deficiencies of both of these prior art systems while retaining the most desirable characteristics and the advantages of both.
As representative of the prior art in these separate areas of the surface finishing field may be mentioned U.S. Pat. Nos. 3,073,078, 3,073,079, 3,073,080, 3,073,081, 3,073,082, 3,073,069, 3,435,567, 3,990,188, 4,026,075, 4,177,608, and U.S. Pat. No. RE 29,964.